GOP redistricting leaves its stamp on 2012 election

New election data shows that five of Wisconsin’s eight U.S. House districts, 17 of 33 state Senate districts, and 56 of 99 state Assembly districts voted Republican for president — even though Mitt Romney lost the state as a whole by nearly 7 points.

Those seemingly odd results are a striking testament to the power of the GOP redistricting plan adopted last year, boosting the number of Republican-friendly seats in Madison and Washington.

That map helped the GOP take back the state Senate and pad its hefty Assembly majority in an otherwise dismal year for the party.

It helps explain a paradox of Wisconsin politics: how to square the GOP’s current dominance in state government with its ongoing futility in presidential elections.

And it underscores just how high a hurdle Democrats face in the next several years in legislative races in Wisconsin, competing on a playing field tilted sharply against them.

An analysis of the numbers shows that 60 of 99 Assembly districts are more Republican than the state as a whole, based on presidential voting. That’s precisely the number of seats Republicans won last month.

And 20 of the 33 state Senate districts are more Republican than the state as a whole. The GOP emerged from the election with 18 Senate seats.

The bottom line: for Democrats to win back the Legislature under the new lines, it’s not enough for them to win battleground districts. They need to win multiple victories on Republican turf.

The new map has one other big consequence along with its partisan skew. It reduces the number of competitive congressional and legislative seats.

There are now very few districts in Wisconsin that mirror the state’s overall partisan balance. To create more “red” Republican seats, the GOP plan moved Democratic voters from competitive districts into ones that were already very “blue.” The result: more lopsided seats on both sides and fewer competitive ones.

But last month’s election provides the first concrete evidence of its impact.

The most revealing numbers can be found in election data posted by the state Government Accountability Board last week: ward-by-ward presidential returns that can be sorted by legislative and congressional district. Presidential voting is not only a useful barometer of the partisanship of a district, but because it’s a national office, it makes it possible to compare the political character of one district to other districts and to the state and nation as a whole.

Here’s what the numbers show, by office:

U.S. House. Five of the state’s eight U.S. House seats voted Republican for president in a year when Republicans lost that election by 6.8 points statewide.

President Barack Obama won Democrat Gwen Moore’s 4th District by 51 points, newly elected Democrat Mark Pocan’s 2nd District by 38 points, and Democrat Ron Kind’s 3rd District by 11 points.

But in districts with Republican incumbents, he lost Jim Sensenbrenner’s 5th District by 24 points; Tom Petri’s 6th District by 7 points; Reid Ribble’s 8th District by 4 points; Paul Ryan’s 1st District by 4 points; and Sean Duffy’s 7th District by 3 points.

The chart below shows the presidential vote in each district, and how it compared with the statewide vote:

Because so many Democratic votes are concentrated in the 2nd District (which includes Dane County) and the 4th District (which includes the city of Milwaukee), Republicans have a numbers advantage elsewhere on the map.

This is partly a consequence of population patterns. Madison and Milwaukee have high concentrations of Democrats. That hurts the party when it comes to drawing district lines, because those Democratic votes would be more helpful if they were spread out across more districts. But the new Republican-friendly map also plays a role here.

Republicans went to great lengths to bolster Duffy, moving three Democratic-leaning cities in central Wisconsin out of his northern Wisconsin seat, held previously by Democrat Dave Obey. Before the changes, the 7th District had been close to 50/50 in its partisan makeup. In presidential voting in 2004 and 2008, it closely mirrored the statewide vote.

But under the new lines last month, it voted 5 points more Republican for president than the state as a whole. Redistricting doesn’t entirely account for Duffy’s re-election, since he won last month with 56% of the vote. But it makes his district significantly safer for him and for the GOP in the future.

The new map also reduces partisan competition overall. While some of the changes were small, every U.S. House seat in Wisconsin that wasn’t safe already became safer for the party that now occupies it.

Wisconsin Senate. In 2008, 18 of 33 Senate districts were more Republican than the state as a whole, based on how they voted for president. Under the new map, 20 are more Republican than the state as a whole, based on their presidential vote (you can see the numbers on all 33 districts here).

If they haven’t locked in control of the state Senate with this map, Republicans have come close. Under the new lines, 15 seats (two shy of a majority) are at least 5 points more Republican than the state as a whole. That was true of only nine seats under the old lines. To win a bare majority (17 seats), Democrats would have to win at least two Senate districts that are Republican enough they voted for a GOP presidential candidate (Romney) who lost decisively statewide.

The decline in competition is striking here, too. In 2008, there were 11 districts within 3 points (in either direction) of the statewide presidential vote. In last month’s election, under the new lines, there were only five.

Wisconsin Assembly. This may be where the effects of the new map are most dramatic: 60 of the 99 seats were more Republican in their presidential voting last month than the state as a whole. Of those, 56 were carried outright by Romney, and another four were won by Obama, but by smaller margins than he won statewide. Only 39 districts were more Democratic than the state as whole.

This is also a significant change from the old map. In 2008, 51 of 99 seats were more Republican than the state as a whole.

The graphic below illustrates the change. The lines represent individual districts, ranked by their partisan makeup. The length of each line shows the difference in points between how each district voted for president and how the state as a whole voted. (Red means a higher Republican vote than the state as a whole; blue means a lower Republican vote):

To increase the number of Republican-friendly districts, the GOP “packed” Democratic voters into fewer districts, making those seats more heavily Democratic but diluting Democratic voting power in other places. The horizontal line across the middle of both charts above represents the 50th seat in 99-member Assembly. The 2012 chart shows how the 50th seat is now about 5 points more Republican than the state as a whole, based on presidential voting. In 2008 the 50th seat was very close to the statewide vote (the vertical line in the middle).

Under the new map, for Democrats to win just a bare majority of 50, they have to win 11 Assembly seats that are more Republican than the state as a whole (based on how they voted for president last month), including seven seats that voted for Romney.

The loss of competition in Assembly races is dramatic.

In 2008, there were 29 districts within 3 points (in either direction) of the statewide presidential vote. In last month’s election, there were only seven such districts. In other words, the vast majority of seats are either now much more Republican or much more Democratic than the state as a whole.

In short, not only is the overall map skewed. But a far greater number of individual districts than before are either locked in for one party or or tilted sharply enough to give one side a serious advantage.

Redistricting isn’t the only factor in the battle over control of the Legislature. Other things matter, too, including the quality of candidates, the way campaigns are run, the election climate and money. But if the playing field isn’t even, then it’s possible for one side to have more statewide support and still lose.

Until the next redistricting nearly a decade from now, the legislative and congressional playing field in Wisconsin is not a level one.

The Wisconsin Voter is a blog about elections, political trends and public opinion in Wisconsin and the Upper Midwest. It is less about politicians than the people who elect them. It’s aimed at political junkies and general readers alike. Its subjects include:

The role this state and region play as electoral battlegrounds.

Voting patterns and trends at the local, state and regional level.

What makes voters here different from voters in other places.

Public opinion and the election climate.

Craig Gilbert is the Journal Sentinel's Washington, D.C. Bureau Chief and national political reporter.

Charting how each of Wisconsin’s 72 counties has trended politically compared to the U.S. as a whole over 60 years of presidential voting. Use the pull down menu to see charts for individual counties. Click here for an explanation of how the charts were done and how to read them.